The mayor owes as much as half a million dollars to the Kramer Levin Naftalis & Frankel law firm — which employs his lawyer, Barry Berke.

Mayor de Blasio owes at least $250,000 to $499,999 to law firm Kramer Levin Naftalis & Frankel — at the same time the firm is actively lobbying his administration.

Hizzoner listed an “unsecured loan” from the white-shoe firm — which represented him in campaign finance and corruption probes — in that price range for 2016 in his financial disclosure with the Conflicts of Interest Board. That wouldn't include legal costs de Blasio incurred in 2017, when the investigation was wrapped up with no charges in March.

Since January 2016 through March, Kramer Levin has lobbied the Office of the Mayor for a total of 45 clients, city records show.

Most of those clients are real estate developers seeking favorable zoning changes or lower property taxes. Several of the developers are builders of affordable housing, a key issue for the mayor.

In 2016 and through the first three months of this year, for example, Kramer Levin has pressed the mayor's office and multiple City Hall agencies on behalf of Douglaston Development. In March the city Housing Preservation & Development Department (HPD) released a list of developers "pre-qualified" to bid on HPD and Housing Authority projects. Douglaston was on that list.

"The Mayor voluntarily discloses when he's lobbied," spokesman Eric Phillips said in an email. "He always has and always will make decisions on the merits, regardless of who's lobbying the administration."

Bronx Borough President Ruben Diaz Jr. reported debts of up to $250G, which his office said was for his son’s college tuition.

(Richard Harbus/for New York Daily News)

The mayor has repeatedly said he was not sure of the total legal bills he owes the firm, which employs his lawyer Barry Berke. But he's said he wants to establish a legal defense fund, which would allow him to raise money to pay off the bills.

That plan hit a snag when COIB issued an advisory opinion saying such donations would qualify as a gift — meaning de Blasio would be limited to $50 donations from anyone who wasn't a close friend or family member.

On Friday Phillips confirmed the mayor has yet to set up his legal defense fund. He also could not provide documentation spelling out the terms of the "unsecured loan" from Kramer Levin.

The mayor's financial disclosures also indicate he owes more than $500,000 on each of the mortgages for the two homes he owns in Park Slope, and has an unsecured loan between $5,000 and $47,999 from HSBC and a JP Morgan Chase-secured loan on a residential property for between $100,000 and $249,999.

De Blasio rents out three units — one home is split into two units. Two of them brought in between $5,000 and $47,999 in income, the other between $48,000 and $59,999.

Queens Borough President Melinda Katz owes as much as $250G to law firm Mintz and Gold, disclosure forms reveal.

Other elected officials in the city also filed their disclosure forms today. Bronx Borough President Ruben Diaz Jr. reported a loan of between $100,000 and $249,999 that his office said was for college tuition for his son. Queens Borough President Melinda Katz reported owing between $100,000 and $249,999 to law firm Mintz and Gold for a civil suit.

"The attorney fees relate to a resolved civil litigation which centered on private family matters. These matters involve young children and we will not be commenting further. Thank you," a spokeswoman said.

Katz also listed the fees last year. The law firm represented her in a 2014 suit over child support from her children's father, Guardian Angels founder Curtis Sliwa.

The disclosures are the first to reflect new salaries and rules for City Council members — including rules barring most kinds of outside income. Council members can still collect income on rental properties, stocks or other investments, and several did.